1. Field of the Invention
The present invention relates to the technical field of dye-sensitized solar cells, in particular, to an organic dye having a rigid donor and a process for producing the same, and a dye-sensitized solar cell.
2. Background Information
Stepping into the 21th century, the energy demand increases dramatically with the fast economic development in China. At present, China has become the largest energy-importing country in the world. Furthermore, environmental problems accompanied with consumption of the ore-based energy, such as fog and haze, are increasing sharply. Therefore, starving for a clean and sustainable energy has continued to prompt the intensive research on the development and utilization of solar energy.
A solar cell is a semiconductor device that can absorb solar light efficiently and convert it to electrical energy. As an important type of solar cells, dye-sensitized solar cells have been widely concerned all over the world. As early as in 1991, Grätzel and his co-workers produced a device by adsorbing RuL2(μ-(CN)Ru(CN)L′2)2 (L=2,2′-bipyridyl-4,4′-dicarboxylic acid, L′=2,2′-bipyridyl), a trinuclear ruthenium dye on a high quality TiO2 nanocrystalline film, which was developed by Grätzel et al. after the intensive study for many years, and a power conversion efficiency of 7.1% was achieved under the simulated AM1.5G sunlight. Thereby, the widely research of dye-sensitized solar cells was launched. When compared with traditional inorganic semiconductor solar cells, dye-sensitized solar cells are low-cost, colorful and good-looking. Furthermore, flexible dye-sensitized solar cells are well known as their lightweight, foldable and windable properties, which can be broadly used in daily life.
The sensitizer is one of the important components of a dye-sensitized solar cell. At present, most of the commercial available sensitizers are complexes containing ruthenium, which is a noble metal. Since the resource of ruthenium is scarce, it is more practical to develop non-metal organic dyes. However, only a few devices made from purely organic dyes can achieve a power conversion efficiency over 10% currently. The poor efficiency has become a crucial obstacle that puzzles the development of purely organic dyes for a long time.